Abrading machinery.



No. 683,669. Patented Out. I, l90l. E. G. THOMAS.

ABRADING MACHINERY.

lApplication filed Feb. 5, 1901.)

(No Model.)

Fic;.2.

WITNESSES INvENTo UNITED STATES PATENT FFICE.

EDWVARD G. THOMAS, OF CAMBRIDGE, MASSACHUSETTS.

ABRADING MACHINERY.

SPECIFICATION forming part of Letters Patent No. 683,669, dated October 1, 1901.

Application filed February 6, 1901. Serial No. 46,106. (No model.)

To all whom, it may concern.-

Be it known that I, EDWARD G. THOMAS, a citizen of the United States, residing at Cambridge, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Abrading Machinery, of which the following is a specification, reference being had to the accompanying drawings, forminga part of this speci fication, in explaining its nature.

My invention relates to machines for producin g a smooth surface on various materials, and more particularly to those machines in which the abrading or polishing material or agent is carried on the surface of a rotating roll or is otherwise given a continuous movement, and is herein shown and described as embodied in a machine which is especially adapted for sandpapering wooden surfaces.

In the use of such machines as heretofore constructed it has been found in many cases that if the normally uniform passage of the machine over the work is temporarlly interrupted, as in changing its direction with respect to the surface operated upon, the rotating roll being held too longin contact with one small portion of said surface abrades that portion to a greater extent than elsewhere, with the result that such excessivelyabraded portion shows on the finished work and disfigures it.

My invention is intended toovercome the defect just described, and to this end I provide means for giving the roll or equivalent surface atranslatory movement with respect to the machine as a whole and in the direction of the travel of the machine with respect to the work operated upon, so that if such travel happens to be stopped momentarily the points of contact between the roll and the work instead of being confined to a fixed line of tangency are continuously shifted 'over a considerable surface, with the result that the abrading action is uniformly distributed over such surface and its effect on any one point or line is correspondingly diminished. I thereby combine the rapidity of action obtainable from arotating roll with the uniformity obtainable from hand-finishing and am enabled to produce machine-finished work without liability to defects such as above described.

Asandpapering-machine embodying a preferred form of my invention is illustrated in the accompanying drawings, in which- Figure 1 shows the machine in side elevation, and Fig. 2 is a bottom plan view thereof.

The machine shown in the drawings comprises a base 2 and a frame 3, mounted thereon and carrying the rotating abradingroll. The machine may be pushed over the surface to be finished by means of handles 4 4, or the work may be moved past the machine while held stationary, rollers 5 5 being preferably provided to reduce the friction. In the frame 3 is journaled a driving-shaft 6, to which power is brought in any suitable manner. The abrading-roll 7 is carried on a shaft 8 and is driven from the shaft 6 by means such as a belt 9 and pulleys 10 and 11, secured to said shafts 6 and 8, respectively. In order-that the roll 7 may be capable of movement as a whole transversely to its axis of rotation, I prefer to journal its shaft 8 in the lower ends of two arms 12 12, which are themselves journaled on the shaft 6, so that the roll 7, together with its shaft 8 and pulley 11, may be moved about the shaft 6 as a center without interfering with'the driving of said roll, and in order to provide for the adjustment of the abrading-surface of the roll with respect to the work the frame 3 may be pivoted at one end to the base 2, as at 13, and supported at its other end by an adj usting-screw 14.

For giving the roll 7 the desired translatory movement I provide a reciprocating mechanism consisting, preferably, of a rock-shaft 15, journaled in the frame 3 and provided with arms 16, connected by links 17 with the shaft 8, said rock-shaft being also provided with an arm 18, connected byalink 19 to a crankpin 20, secured to one end of the drivingshaft 6. In order to prevent vibrations of the roll from being shared in part by the frame of the machine, I provide counterbalances 21 21, which by their motion in the op posite direction from that of the roll prevent anyiendency to vibratory motion in the frame of the machine.

In operation the shaft 6, through its connections with the shaft 8, simultaneously ro-' tates the roll 7 and reciprocates it bodily in the direction of travel of the work with respect to the machine, the result being that even if the travel of the work is stopped entirely the abrading-point of the roll still contin ues to be shifted over the surface operated upon, so that it is impossible for the roll to cut a disfiguring-line on any portion of said surface.

It will ordinarily be desirable to cause the roll 7 and arms 12 to reciprocate through such an angle .that at each end of its path said roll will move out of contact with the surface operated upon, since in such case the abrading action will diminish to zero at the edges of that portion of the surface over which it is reciprocated, and hence will be unable to define said edges with sufficient sharpness to make them visible as a disfigurement on the finished work. The machine may readily be made to operate in this manner by regulating the position of the roll by means of the ad justing-screw 14-.

I am aware that "arious kinds of abradingmachines have heretofore been provided with rotating rolls which were reciprocated axially; but such a construction is of no assistance in overcoming the liability to disfigurement above described, .because the points of contact between such a roll and the work are still confined to a fixed line of tangency in any given position of the work with respect to the machine. I am also aware that abrading-machines have heretofore been used in which the abrading-roll is given a reciproeating movement transversely to its axis for the'purpose of causing it to act upon the entire width of a given surface of limited length, said surface being fed in a direction parallel to the axis of such roll; but said reciprocation is in reality a feed movement and does not embody nor serve the purpose of my invention, and I do not claim the same. So far as I am aware, however, I am the first to reciprocate a rotating roll transversely to its axis and in the general direction of its travel with respect to the surface to be abraded, and thus to distribute its action over a considerable surface of the work operated upon, regardless of the travel of the latter through the machine, and hence I do not consider my invention to be limited to any particular kind or construction of rotating roll or abrading-snrface or to any specific mechanism-for mounting, rotating, or reciprocating the same. It is not necessary that the roll 7 should be reciprocated in a direction at right angles to its axis, as a reciprocation of the cutting-point of the roll or other abrading-surface in any path, straight or curved, will be effective, provided such path makes an angle with the line of contact of said cuttingpoint and the surface of the work.

I claim as my invention 1. In an apparatus of the character described, the combination of a frame,an abrading-surface carried thereby and having a continuously-progressive movement, and means for giving its cutting-point a limited reciprocation in the general direction of the travel of said frame with respect to the work operated upon, for the purpose set forth.

2. In an apparatus of the character described, the combination of an abrading-roll, means for supporting and rotating the same, means for adj usting said roll toward and from the work operated upon, and means for giving it a limited reciprocation transversely to its axis and in the general direction of its travel with respect to said work, for the purpose set forth.

3. In an apparatus of the character described, the combination of a frame, an abrading-roll carried thereby, means carried by said frame for rotating said roll and simultaneously reciprocating it transversely to its axis, and means for adjusting said frame and roll toward and from the work.

4. In an apparatus of the character described, the combination of a base adapted to bear against the surface operated upon and capable of unlimited longitudinal movement with respect to the same, a frame carried by that side of said base which is opposite tothe work, an abrading-roll carried by said frame and having its cuttingpoint projecting through said base into contact with the work, and means for reciprocating said roll transversely to its axis.

5. In an apparatus of the character described, the combinationof a frame, an abrading-roll carried thereby, means for rotating said roll, counterweighted arms journaled on said frame and links connecting the same to the axis of said roll, and means for oscillating said arms.

6. In an apparatus of the character described, the combination of a frame 3, means for supporting the same, a shaft 6 journaled in said frame, an abrading-roll 7 suspended by arms 12 from said shaft 6, a rock-shaft 15 journaled in said frame and provided with arms 16 and 18, links 17 connecting the arms 16 with the axis of the roll 7, a link 19 connecting the arm 18 with a crank-pin 20 on the shaft 6, and means'for rotating said shaft, substantially as described. 7

In testimony whereof I have hereunto subscribed my name this 1st day of February, 1901.

EDWARD G. THOMAS.

Witnesses:

F. E. ROBERTSON, W. H. BOYNTON. 

